What EPA's radon map says about Salem County

Salem County is mapped as Zone 2 - Moderate Potential by EPA — meaning the county-wide average indoor level is predicted between 2 and 4 pCi/L. That puts Salem County in the 57th percentile nationally for radon potential — higher than 57% of the counties EPA has rated.

Salem County by the numbers

About 65,874 people live in Salem County, New Jersey, spread over 331.861 square miles. That works out to roughly 198 people per square mile. Among counties sharing Salem County's EPA zone, it outranks 73% of them by population. Salem County falls in EPA Radon Region 2, one of 83 counties nationally EPA assigns to that same geologic province.

What this actually means for a house in Salem County

Call it a middle case: above the 1.3 pCi/L most US homes average, below the 4 pCi/L line EPA uses to recommend mitigation — that's Salem County's Zone 2 prediction. Nothing about a Zone 2 label lowers the case for testing in Salem County — EPA recommends it in every zone, moderate included.

If Salem County tests above the action level

Mitigation cost doesn't depend on Salem County's zone — it depends on the house's foundation. A typical system runs $800–$2,500 (about $1,200 typical), and testing first is what tells you whether that's needed at all.

Find New Jersey's state radon program

Salem County's test kit answers today; a Airthings radon monitor keeps answering for Salem County over time. Affiliate link, RadonZoneCheck earns a commission there, at no extra cost to you. Code RADONZONE-10OFF takes 10% off at checkout.

More on how this number was built

Salem County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.